Radiation emitted from artificial or natural sources is one of the major causes of opthalmic damage including formation of cataracts and tissue damage in the retina, the lens and the cornea. It is believed that a portion of the damage to the cornea and probably the lens is attributed to superoxide being formed in the cornea as a result of the reaction of oxygen with biological molecular units of the cornea being brought to an electronically excited state by light reaching the cornea.
With respect to retinal damage and cataract formation, it is known that, although the cornea and the lens of the eye absorb a large portion of the ultra-violet rays emitted from the radiation source, a substantial portion of the radiation in the range of wavelengths between 400 and 550 nanometers reaches the retina and causes photochemical damage. The amount and severity of the damage increases exponentially as the wavelength of the radiation decreases towards 400 nanometers. The correlation between retinal damage and wavelength is defined herein as the action spectrum for retinal damage.
In the past, various opthalmic devices were developed to absorb radiation. Although some of those devices were able to filter out ultra-violet radiation, most of those devices cut out the ultra-violet wavelengths abruptly as do cut off filters, while allowing radiation between the wavelengths of 400 and 550 nanometers to go through and adversely affect the eye. Furthermore, nobody has attempted to reduce the effects of the superoxide being formed in the cornea and the vicinity thereof.
The present invention discloses an apparatus and a method for absorbing radiation throughout the ultra-violet, visible and infra-red region, including radiation in the wavelengths between 400 and 550 nanometers. Furthermore, it discloses an apparatus and a method for absorbing radiation throughout the entire ultra-violet, visible and infra-red spectrum with the amount of radiation being absorbed increasing as the wavelength increases whereby the absorption is proportionately higher in the regions wherein the effect of radiation is more harmful. Furthermore, the present invention discloses a method and apparatus for reducing the perceived harmful effects of superoxides present in the cornea by scavenging those superoxides. The apparatus and method utilize a hydrophilic contact lens which includes melanin in a non-aggregated form. The melanin provides an absorption spectrum throughout the entire ultra-violet, visible and infra-red region which is similar to the action spectrum for retinal damage. Furthermore, the melanin scavenges the superoxide that is present in the vicinity of the cornea and prevents it from adversely reacting with excited biological tissue. Although melanin has been disclosed in the past as a sunscreen mixed in a cosmetic cream applied to the skin in Japanese Patent 74 71,149 to Kokai, that melanin was in aggregated form and not suitable for the apparatus and the method of the present invention.
These and other advantages over the present invention will become apparent from the following description and drawing.